Uptake of amino acids in reconstituted vesicles derived from plasma membranes of ehrlich ascites cells

✍ Scribed by R. M. Johnstone; Claudette Bardin

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 357 KB
• Volume: 89
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1040890446

✦ Synopsis

Abstract

To obtain a clearer concept of the mechanism of organic solute transport in mammalian cells, we have attempted to reconstitute a functional transport system for amino acids from plasma membranes of Ehrlich ascites cells. Purified plasma membranes were dissolved in 2% Na cholate—4 M urea, a mixture which brought over 85% of the membrane proteins into solution. After centrifugation of the solubilized material for 2 hrs at 100,000 × g, the supernatant was dialyzed in the cold for 20 hrs with additional lipid. The reformed vesicles were tested for the ability to transport amino acids. The preliminary results obtained show that the uptake of α‐aminoisobutyric acid can be inhibited by L‐methionine and much less by L‐leucine as would be predicted from the known properties of α‐aminoisobutyrate transport in the intact cells. In addition, it has been possible to show accelerated efflux of intravesicular phenylalanine when phenylalanine is added to the trans side (medium side). The data are consistent with the conclusion that there is carrier mediated transport in the reconstituted vesicles.